The present disclosure relates to polycarbonate compositions that have a combination of low temperature impact resistance, thin wall flame retardance (FR), good electrical tracking resistance, and reduced halogen content. These polycarbonate compositions can be useful for various applications.
Polycarbonates (PC) are synthetic engineering thermoplastic resins, and are a useful class of polymers having many beneficial properties. Polycarbonate resins are used for a number of different commercial applications, including electronic engineering (E&E) parts, mechanical parts and so on. Because of their broad use, it is desirable to provide polycarbonates having good flame retardance. The market is also moving towards articles having thin walls for purposes of slimness, weight reduction, and size reduction of the overall final product, as well as more complex designs.
Desirably, polycarbonate compositions should also have good flow properties. Good flow properties reflect how easily the polymeric composition can be poured into a mold for forming the shape of the part. Better impact properties are also desirable. A conventional way of increasing stiffness is by increasing the weight average molecular weight of the polymer, but this typically also reduces the flow properties and makes it difficult to fill complex or thin-walled molds. Common flame retardant additives do not provide this balance between properties.
There remains a need in the art for flame retardant polycarbonate compositions that have good thin wall flame retardance, provide good electrical tracking resistance, and maintain ductility at low temperatures while providing the desired color. This need is especially apparent when high levels of TiO2 are needed.